Matrix Recruitment and Calcium Sequestration for Spatial Specific Otoconia Development

Otoconia are bio-crystals anchored to the macular sensory epithelium of the utricle and saccule in the inner ear for motion sensing and bodily balance. Otoconia dislocation, degeneration and ectopic calcification can have detrimental effects on balance and vertigo/dizziness, yet the mechanism underlying otoconia formation is not fully understood. In this study, we show that selected matrix components are recruited to form the crystal matrix and sequester Ca2+ for spatial specific formation of otoconia. Specifically, otoconin-90 (Oc90) binds otolin through both domains (TH and C1q) of otolin, but full-length otolin shows the strongest interaction. These proteins have much higher expression levels in the utricle and saccule than other inner ear epithelial tissues in mice. In vivo, the presence of Oc90 in wildtype (wt) mice leads to an enrichment of Ca2+ in the luminal matrices of the utricle and saccule, whereas absence of Oc90 in the null mice leads to drastically reduced matrix-Ca2+. In vitro, either Oc90 or otolin can increase the propensity of extracellular matrix to calcify in cell culture, and co-expression has a synergistic effect on calcification. Molecular modeling and sequence analysis predict structural features that may underlie the interaction and Ca2+-sequestering ability of these proteins. Together, the data provide a mechanism for the otoconial matrix assembly and the role of this matrix in accumulating micro-environmental Ca2+ for efficient CaCO3 crystallization, thus uncover a critical process governing spatial specific otoconia formation

MOLECULAR STRUCTURE OF THE EPIDERMAL EXTRACELLULAR SPACES

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65966/1/j.1365-4362.1979.tb01946.x.pd

Organization and training at national level of antimicrobial stewardship and infection control activities in Europe: an ESCMID cross-sectional survey

Antimicrobial stewardship (AMS) and Infection prevention and control (IPC) are two key complementary strategies that combat development and spread of antimicrobial resistance. The ESGAP (ESCMID Study Group for AMS), EUCIC (European Committee on Infection Control) and TAE (Trainee Association of ESCMID) investigated how AMS and IPC activities and training are organized, if present, at national level in Europe. From February 2018 to May 2018, an internet-based cross-sectional survey was conducted through a 36-item questionnaire, involving up to three selected respondents per country, from 38 European countries in total (including Israel), belonging to the ESGAP/EUCIC/TAE networks. All 38 countries participated with at least one respondent, and a total of 81 respondents. Education and involvement in AMS programmes were mandatory during the postgraduate training of clinical microbiology and infectious diseases specialists in up to one-third of countries. IPC was acknowledged as a specialty in 32% of countries. Only 32% of countries had both guidance and national requirements regarding AMS programmes, in contrast to 61% for IPC. Formal national staffing standards for AMS and IPC hospital-based activities were present in 24% and 63% of countries, respectively. The backgrounds of professionals responsible for AMS and IPC programmes varied tremendously between countries. The organization and training of AMS and IPC in Europe are heterogeneous and national requirements for activities are frequently lacking

hCEACAM1-4L downregulates hDAF-associated signalling after being recognized by the Dr adhesin of diffusely adhering Escherichia coli.

International audienceHuman decay accelerating factor (hDAF, CD55) and members of the carcinoembryonic-antigen-related cell-adhesion molecules (hCEACAMs) family are recognized as receptors by Gram-negative, diffusely adhering Escherichia coli (DAEC) strains expressing Afa/Dr adhesins. We report here that hCEACAM1-4L has a key function in downregulating the protein tyrosine Src kinase associated with hDAF signalling. After infecting HeLa epithelial cells stably transfected with hCEACAM1-4L cDNA with Dr adhesin-positive E. coli, the amount of the pTyr(416)-active form of the Src protein decreased, whereas that of the pTyr(527)-inactive form of Src protein did not increase. This downregulation of the Src protein implies that part of the hCEACAM1-4L protein had been translocated into lipid rafts, the protein was phosphorylated at Tyr residues in the cytoplasmic domain, and it was physically associated with the protein tyrosine phosphatase, SHP-2. Finally, we found that the hCEACAM1-4L-associated SHP-2 was not phosphorylated and lacked phosphatase activity, suggesting that the downregulation of Src protein associated with hDAF signalling results from the absence of dephosphorylation of the pTyr(527)-inactive form necessary for Src kinase activation